Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0023241 (Legionella)
 6,990 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The authors report a nonradioactive adaptation of DNA hybridization technology for the direct detection of Legionella organisms in situ in routinely processed histologic specimens. The probe used consisted of synthetic oligodeoxynucleotides, complementary to the ribosomal RNA of all clinically relevant Legionella species, labeled with biotinylated dUTP at their 3' ends. By in situ DNA hybridization and detection with an avidin-alkaline phosphatase complex. Legionella was visualized by light microscopy within the alveoli of lung specimens in 9 of 13 direct fluorescent antibody- or culture-positive cases of Legionnaires' disease. No cross-hybridization was observed in lung specimens infected with Pseudomonas aeruginosa, Klebsiella pneumoniae, Streptococcus pneumoniae, or other pathogens. The authors' results illustrate a novel adaptation of in situ DNA hybridization techniques, usually used for viruses, to the detection of a bacterial organism. The method enables direct visualization of bacterial nucleic acid in infected tissues and may facilitate early diagnosis and treatment of legionellosis.
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PMID:Rapid diagnosis of Legionella infection by a nonisotopic in situ hybridization method. 202 27

Detection of pathogens (Legionella species) and indicator bacteria (coliform bacteria) was achieved by multiplex (simultaneous) PCR amplification of diagnostic gene sequences and by hybridization to immobilized poly-dT-tailed capture probes using a dot- or slot-blot approach. Complex manipulations of primer concentrations and staggered additions of primers were required in order to achieve equal amplification of multiple genes. Multiplex PCR amplification of two different Legionella genes, one specific for L. pneumophila (mip) and the other for the genus Legionella (5S rRNA), was achieved by staggered amplification. Multiplex PCR amplification using differing amounts of primers specific for lacZ and lamB genes permitted the detection of coliform bacteria and those associated with human faecal contamination, including the indicator bacterial species E. coli and enteric pathogens Salmonella and Shigella. Hybridization of biotin-labelled amplified DNA, in which the biotin was incorporated during PCR amplification from biotinylated-dUTP, to immobilized 400-dT-tailed capture probes permitted specific and sensitive detection of target gene sequences. The sensitivity of colorimetric detection achieved by PCR amplification of target DNA was at a level equivalent to 1-2 bacterial cells, which is the same level of sensitivity obtained with radioactive detection. The simultaneous amplification of several genes and hybridization to immobilized capture probes with colorimetric detection is an effective, efficient and rapid detection method for various human bacterial pathogens.
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PMID:Multiplex PCR amplification and immobilized capture probes for detection of bacterial pathogens and indicators in water. 228 Jul 81

The hallmark of Legionnaires' disease is intracellular replication of Legionella pneumophila within cells in the alveolar spaces. Cytopathogenicity of this bacterium to the host cell has been well demonstrated, but the mechanisms of host cell death due to infection by L. pneumophila are not well understood. In this study, induction of apoptosis in macrophages and alveolar epithelial cells by L. pneumophila during early stages of infection was confirmed by using multiple criteria, including DNA fragmentation by agarose gel electrophoresis, terminal deoxynucleotidyltransferase-mediated dUTP nick end labeling, surface exposure of phosphatidylserine, and cellular morphology by transmission electron microscopy. Induction of nuclear apoptosis in L. pneumophila-infected macrophages is mediated by activation of the caspase cascade death machinery. We provide genetic and biochemical evidence that L. pneumophila-induced apoptosis in macrophages and alveolar epithelial cells does not require intracellular bacterial replication or new protein synthesis. In addition, extracellular L. pneumophila is capable of inducing apoptosis. Furthermore, induction of apoptosis by L. pneumophila correlates with cytopathogenicity. We conclude that L. pneumophila-induced apoptosis in macrophages and alveolar epithelial cells plays an important role in cytopathogenicity to the host cell during early stages of infection.
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PMID:Apoptosis in macrophages and alveolar epithelial cells during early stages of infection by Legionella pneumophila and its role in cytopathogenicity. 991 1